Mode of preparing finely-divided or colloid indigo dyestuffs.



i so parts of iii-oxybenzuldehyde, or about low fiLBREQHT SCHMIDT AND ADDl-F STEINDORFF, OE HsiiCEST-QN-THE-MAIN, QELB-IB lA-HY,

.ASSIG-NGRS TO FARBV/ERKE VORIII. MEISTER LUCZUS BBJj'NING, Q1? E'OTCHQ'gQfl- THE-HAZEL GERMANY, CORPORATION OF GEZA'EANY.

B50352 OF .PRE'PARING FINELY-DIVIDEI) 0E COLLQID INDIGO DYEEEUFES,

I? ma n concern A town that we, ;\LBRE"HT SCHMIDT, Ph. 1)., chemist. and ilnoLr S'rnmoourr. Ph. D, chemist, citizens of the Empire of Germany, residing at Htichst-on-the-ltlain, Germany, have invented certain new and useful improvements in the Mode of Pre paring Finely-Divided or Colloid Indigo Dyestuiis, of which the following is a specification.

In U. S. Letters Patent Numbers 1,058,019 and 1,058,020, granted April 1, 191, to Albrecht Schmidt, assignor, there are described methods of producing a new colloidlike synthetic indigo, in the form of paste, powder or lumps, by liberating the indigo from indol derivatives and indigo salts, specifically leuco salts. in the presence of aronis ic acids, such as sulfonic and carboxylic acids. We have now further found that aldehydes also act similarly to the aromatic sul'tonic carboxylic acids, and that not only aromatic aidehydes but also aldehydes of the fatt-yand the terpene series are edicacious. Thus, for instance, m-oxybenzuldehyde. formaldehyde and the like produce a striking et iect if added when the indigo is caused to form from its salts, including both the salts ot'the indigo itself and those of its minced leucc form, '5. 6., of indigo white. Therefore by passing air into indigo white salts in the presence of these uldchydes, or by decomposing indigo salts containing: a. mineral acid with water in the presence of the aldehydes, the indigo ob taiued in extremely fine subdivision. Furthermore, an ezztremely finely-divided colloid-like indigo can be produced by starting; from completelyfinished tori-naldeh ;deindigo-whites and treating them with sir in presence of alkalis.

Example If 100 parts by weight of an indigo vat oi also. 39970 streng h are intro duced into 2W0 parts of water while adding parts of a 095 solution of tor'meldehyd and then immediately treated with air un the inch-" o has seoarated. The condensation ,33 1 i 1 A 1 produrt; which. torm interniediateiy when tornialdehy c is used, is, if it is formed at aii so run 3 in any case decomposed immeniatelv dyestufi thus 0o l a v 3a ya Y A tamed is extremely chided. it nos Specification of Letters Patent.

etentedilenfit, 51 1 Application filed May 17, 1911. Boris) E0. 6217329.

under which term we comprise for instance the cold glucose vat, the fermentation vat,

and the like. With water, it 'ves a deep-' blue, difiicultly depositin iquid paste, which, on being put on a fi ter, ives a blue filtrate, in which, when seen t rough the' microscope, no more crystalline indigo-partlcles can be discerned. I 1

Example 11: 100 parts by weight of indigo are introduced into 600 parts of sul-. furic acid of while adding 20 parts of a solution of ormaldehyde of 40% strength,

or about 300 parts of m-oxybenzaldehyde.

After having stirred the mass for a longer time it is poured on ice-water. filtered and washed.

,Ekaniple H1: 100 parts by weight of formaldehyd indigowhite in the form of a paste are a irred in presence of air while adding 30 parts of caustic soda-lye of 4:0"

Be. and 2000 parts 0L water. The veryfi'nelydivided indigo thus separated is filtered and washed with water. It entirely resembles in its properties the products described in tile foregoing Examples I and II. The substitution products of indigo; its analogues; also other indigoid dyestuiis and dyestuffs the thioind-igoscries, show a like behavior to the indigo.

Having now described our invention, what we claim is:

1. The process of manufacturing a new form of synthetic indigo bodies, which consiscs in subjecting indigo salts to indigo-pro ducing conditions in the presence of aldehydes. I

2. The process of manufacturing a new form of synthetic in 'go bodies, which con sis-s in subjecting inoigo salts to indigo-pro dnciug conditions: in the presence of formaldehyde.

The process of manufacturing-a new form of synthetic indigo bodies. which cons sts subjecting leuco indigo salts to uni:

'. n in the presence 'olf aldehydes.

4E. The process of manufacturing a new form of synthetic indigo bodies, which consists in subjecting leuco indigo salts to oz-zielation in the presence of formaldehyde.

' 5. The process of manufacturing a new form of synthetic indigo bodies, which consists in oxidizing an alkaline solution of formaldehyde indigo-White salt with air.

8. :is new products, synthetic indigo bodies in the new physical forms which are characterized. by bein easily reduced by slightly alkaline reducing agents, by showing a greenish-blue color, and by yielding, when made up into a paste with water, a

deep-blue difiicnltly-(lepositing liquid paste which, on being puton e filter, gives a blue filtrate, in which, when seen through the mi- Q croscope, no more crystalline indigo-particles can be discerned.

7. As new products, synthetic indigo bodies in the form of a. paste, characterize-i by being easily reduced by slightly alkaline reducing agents, by showing a greenish-blue color, and. by yielding, on being put on e filteign blue filtrate, in which, when seen through the microscope, no more crystalline indigo-particles can be discerned.

In testimony whereof, we afiix our si.gnn tures in presence of two witnesses.

ALBRECHT SCHHIDT. ADOLF STEINDORFF,

Witnesses:

. JEA GRUND, CARL GRUND. 

